1. Field of the Invention
An aspect of this disclosure relates to a substrate carrying device.
2. Description of the Related Art
Substrates such as wafers and reticles (photomasks) used in a process of producing semiconductor devices are generally stored in a container. When a substrate is processed in a semiconductor device production process, the substrate is taken out of the container and carried into a semiconductor production apparatus by a “hand” attached to a carrying arm. Then, a desired process such as etching, film deposition, exposure, washing, or inspection is performed by the semiconductor production apparatus on the substrate. After being processed, the substrate is carried out of the semiconductor production apparatus, and carried to another position for the next process.
When the substrate is carried, to prevent the substrate from falling off the hand, the substrate is vacuum-suctioned by an evacuation mechanism connected to a vacuum suction pad provided on the hand (see, for example, Japanese Laid-Open Patent Publication No.08-017896).
Here, a substrate sometimes warps. Particularly, when a substrate is heated to a high temperature during a process, the substrate tends to warp when it is carried. Also, as the size of a substrate increases and its thickness decreases, the amount of warpage of the substrate being carried tends to increase. When a substrate warps, a gap is formed between the vacuum suction pad and the substrate, and it becomes difficult to vacuum-suction the substrate due to leakage caused by the gap. When vacuum-suctioning the substrate becomes difficult, the risk that the substrate falls off the hand increases and it becomes difficult to carry the substrate.
Meanwhile, when a vacuum suction pad is damaged, it is preferable that the damaged vacuum suction pad is replaceable without replacing the hand to reduce the lead time and costs necessary for the replacement.